The commercial application of an optical system often hinges on the life-time of the system and thereby the life-time of each component. In this context life-time is often measured in the number of operational hours before failure or before performance drops below a specified level. Depending on the application components are exchanged well before expiration of their life-time to ensure continuous high performance of the system. Some systems may monitor the performance in order to determine when one or more components should be exchanged. In either case an exchange of components may be costly, as it will often require the visit of a service technician or shipping the system to a repair facility.